Why is it nicknamed the 'Death Road'?

Wrecked cars and trucks line the road, and so do rows of empty, bombed-out buildings. Castello Road is a long way from a regular commute. "The road smelled of rotten flesh, burnt metal, there were plumes of smoke from ordnance that had fallen previously," said Dr. Samer Attar, who used the highway to go to Aleppo in July. With every minute, it felt like death was just around the corner.

"The driver was really fast and at every moment you felt like you would get hit by a bomb or a missile or bullet," he says.

Such scenes explain why aid agencies are staying away.

What's the connection to the ceasefire?

One word: accessibility.

No access to Castello Road means no aid to areas badly hit in Aleppo. Forces loyal to the Syrian government took over the road in July, and opposition fighters' attempts to retake it have failed.

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The ceasefire deal negotiated by the US and Russia stipulated that pro-government forces allow safe access by vacating the contested highway. The road has "special status" under the agreement, said the UN's special envoy for Syria, Staffan de Mistura.

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Aid agencies have said they need reassurances from both government and opposition groups to use the road to deliver aid.

De Mistura said the two brokers of the deal, Russia and the US, are expected to produce a plan for disengagement from the road, and "are working hard to achieve that."

He would not say how much of the road is expected to be opened to allow unimpeded movement of UN convoys, but that "it urgently needed to take place."

A child carries a canister filled with water near Aleppo's Castello Road.

Once an agreement is reached, there would be "special checkpoints" set up for the aid convoys, he said.

Russian officials have said the Syrian military is ready to pull out of the highway to allow safe passage of humanitarian aid into the city, Russian state news agency Tass reported.

Syria has not confirmed or reported this news, leaving aid agencies unsure whether to access the road. Russian forces have joined their Syrian counterparts in manning the route, making the issue even more complicated.

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Aid convoys are positioned at the border town of Cilvegozu, poised to enter the country and deliver food and medical aid to rebel-controlled eastern Aleppo, where the United Nations says between 250,000 and 275,000 people have been cut off from assistance since early July.

The trucks are carrying enough to feed 40,000 people for an entire month.